Fuel channel annulus spacer

Abstract

An annulus spacer for a fuel channel assembly of a nuclear reactor. The fuel channel assembly includes a calandria tube and a pressure tube positioned at least partially within the calandria tube. The annulus spacer includes a garter spring configured to surround a portion of the pressure tube to maintain a gap between the calandria tube and the pressure tube. The garter spring includes a first end and a second end. The annulus spacer also includes a connector coupled to the first end and the second end of the garter spring. The connector allows movement of the annulus spacer when the pressure tube moves relative to the calandria tube during thermal cycles of the fuel channel assembly. The annulus spacer further includes a girdle wire positioned substantially within the garter spring and configured to form a loop around the pressure tube.

1 . An annulus spacer for a fuel channel assembly of a nuclear reactor, the fuel channel assembly including a calandria tube and a pressure tube positioned at least partially within the calandria tube, the annulus spacer comprising:
 a garter spring configured to surround a portion of the pressure tube to maintain a gap between the calandria tube and the pressure tube, the garter spring including a first end and a second end;   a connector coupled to the first end and the second end of the garter spring, the connector allowing movement of the annulus spacer when the pressure tube moves relative to the calandria tube during thermal cycles of the fuel channel assembly; and   a girdle wire positioned substantially within the garter spring and configured to form a loop around the pressure tube.   
     
     
         2 . The annulus spacer of  claim 1 , wherein the first end and the second end of the garter spring are coupled to the connector such that the garter spring forms a toroid. 
     
     
         3 . The annulus spacer of  claim 2 , wherein the garter spring is expandable to a dimension greater than an outside diameter of the pressure tube during installation, and wherein the garter spring is resilient to fit tightly around the pressure tube once installed. 
     
     
         4 . The annulus spacer of  claim 1 , wherein the connector includes one or more fusion welds connecting the first end and the second end of the garter spring. 
     
     
         5 . The annulus spacer of  claim 1 , wherein the connector includes a first hinge coupled to the first end of the garter spring, a second hinge coupled to the second end of the garter spring, and a cross-shaft coupling the first hinge to the second hinge, and wherein the cross-shaft allows the first hinge and the second hinge to pivot to maintain the flexibility of the garter spring. 
     
     
         6 . The annulus spacer of  claim 1 , wherein the connector includes a tubular member extending between the first end and the second end of the garter spring, and wherein the tubular member helps maintain the flexibility of the garter spring. 
     
     
         7 . The annulus spacer of  claim 1 , wherein the connector includes a first portion coupled to the first end of the garter spring and a second portion coupled to the second end of the garter spring, wherein the first portion includes a spherical boss that is inserted into the second portion to couple the first portion and the second portion together, and wherein the spherical boss allows the first portion and the second portion to pivot to maintain the flexibility of the garter spring. 
     
     
         8 . The annulus spacer of  claim 1 , wherein the connector includes a flexible bellows extending between the first end and the second end of the garter spring, and wherein the flexible bellows is bendable to maintain the flexibility of the garter spring. 
     
     
         9 . The annulus spacer of  claim 1 , wherein the connector includes a first connector coupled to the first end of the garter spring, a second connector coupled to the second end of the garter spring, and a flexible conduit extending between the first connector and the second connector, and wherein the flexible conduit is bendable to maintain the flexibility of the garter spring. 
     
     
         10 . The annulus spacer of  claim 1 , wherein the connector includes a first connector coupled to the first end of the garter spring and a second connector coupled to the second end of the garter spring, wherein the first connector includes a projection and the second connector includes a recess, and wherein the projection is received in the recess to lock the first connector and the second connector together. 
     
     
         11 . The annulus spacer of  claim 1 , wherein the connector includes a first portion coupled to the first end of the garter spring and a second portion coupled to the second end of the garter spring, wherein the first portion includes a cylindrical boss that is inserted into the second portion to couple the first portion and the second portion together, and wherein the cylindrical boss allows the first portion and the second portion to rotate relative to each other to maintain the flexibility of the garter spring. 
     
     
         12 . The annulus spacer of  claim 1 , wherein the connector includes a flange, and wherein one of the first and second ends of the garter spring wraps around a portion of the connector and engages the flange to inhibit the one of the first and second ends from sliding off of the connector. 
     
     
         13 . The annulus spacer of  claim 1 , wherein the connector includes a groove, and wherein one of the first and second ends of the garter spring is positioned within the groove to connect the one of the first and second ends to the connector. 
     
     
         14 . The annulus spacer of  claim 1 , wherein the connector includes a hole, and wherein one of the first and second ends of the garter spring is bent into the hole to inhibit the garter spring from unraveling from the connector. 
     
     
         15 . The annulus spacer of  claim 1 , wherein the girdle wire includes a first segment and a second segment that are welded together to form a continuous loop. 
     
     
         16 . An annulus spacer for a fuel channel assembly of a nuclear reactor, the fuel channel assembly including a calandria tube and a pressure tube positioned at least partially within the calandria tube, the annulus spacer comprising:
 a garter spring configured to surround a portion of the pressure tube to maintain a gap between the calandria tube and the pressure tube; and   a girdle wire positioned substantially within the garter spring and configured to form a loop around the pressure tube, the girdle wire including a first segment and a second segment that overlaps the first segment to form an overlap, the overlap extending between approximately 45 degrees and approximately 135 degrees to reduce the possibility of girdle wire twisting.   
     
     
         17 . The annulus spacer of  claim 16 , wherein the overlap of the girdle wire extends between approximately 75 degrees and approximately 105 degrees. 
     
     
         18 . The annulus spacer of  claim 16 , wherein the pressure tube has a first diameter and the girdle wire is pre-formed with a second diameter, and wherein the second diameter is less than the first diameter such that girdle wire compresses around the pressure tube when the annulus spacer is installed in the fuel channel assembly. 
     
     
         19 . The annulus spacer of  claim 16 , wherein the first segment of the girdle wire is welded to the second segment of the girdle wire to form a continuous loop. 
     
     
         20 . The annulus spacer of  claim 16 , wherein the girdle wire includes a kink formed in one of the first segment and the second segment, and wherein the kink obstructs relative motion between the first segment and the second segment. 
     
     
         21 . The annulus spacer of  claim 16 , wherein the girdle wire has a u-shaped cross-section, and wherein the second segment nests with the first segment to minimize lateral relative movement between the first segment and the second segment. 
     
     
         22 . The annulus spacer of  claim 16 , wherein the girdle wire has a v-shaped cross-section, and wherein the second segment nests with the first segment to minimize lateral relative movement between the first segment and the second segment. 
     
     
         23 . The annulus spacer of  claim 16 , wherein the garter spring includes a first end and a second end, and wherein the first end of the garter spring is coupled to the second end of the garter spring such that the garter spring forms a toroid. 
     
     
         24 . The annulus spacer of  claim 23 , wherein the first end of the garter spring is welded to the second end of the garter spring. 
     
     
         25 . A method of manufacturing an annulus spacer for a fuel channel assembly of a nuclear reactor, the method comprising:
 providing a garter spring wire having a trapezoidal cross-section, a first end, and a second end;   winding the garter spring wire into a coil to induce compressive strain on an inner portion of the trapezoidal cross-section and tensile strain on an outer portion of the trapezoidal cross-section such that the garter spring wire obtains a rectangular cross-section;   positioning a girdle wire within the coil formed by the garter spring wire; and   coupling the first end of the garter spring wire to the second end of the garter spring wire to form a toroid.   
     
     
         26 . The method of  claim 25 , wherein coupling the first end of the garter spring wire to the second end of the garter spring wire includes welding the first end of the garter spring wire to the second end of the garter spring wire to form the toroid. 
     
     
         27 . The method of  claim 25 , further comprising providing a connector, and wherein coupling the first end of the garter spring wire to the second end of the garter spring wire includes coupling the first end of the garter spring wire to the connector and coupling the second end of the garter spring wire to the connector to form the toroid. 
     
     
         28 . The method of  claim 25 , wherein the girdle wire includes a first segment and a second segment, and further comprising overlapping the first segment with the second segment to form a loop with the girdle wire. 
     
     
         29 . The method of  claim 25 , wherein the girdle wire includes a first segment and a second segment, and further comprising welding the first segment to the second segment to form a loop with the girdle wire.